PointCloudReplacer
Typical Uses
- Restoring point clouds previously extracted into an attribute by the PointCloudExtractor, often used to store point clouds as Blobs in non-spatial databases.
- Creating geometry from point clouds read with an AttributeFileReader transformer.
How does it work?
The PointCloudReplacer receives features of any geometry type (or no geometry) that have point clouds stored as Blob attribute of the feature, most often a result of having previously used the PointCloudExtractor to store them as Blob attributes to meet format or processing requirements.
The format of the encoded Blob point cloud must be provided. The attribute storing the Blob may be optionally removed after decoding and replacing the feature’s geometry with the point cloud. Removing the attribute reduces feature size and memory usage, and may improve performance.
Examples
Example: Decoding a point cloud stored in a non-spatial database
In this example, we will retrieve and decode a point cloud that was previously encoded with a PointCloudExtractor and loaded to a non-spatial database.
A database reader (PostgreSQL, in this case) reads the feature from the database table, which is then routed into a PointCloudReplacer.
Examining the feature as it exits the database reader, note that it has no geometry.
The first two attributes - _pointcloudblob and _pointcloudformatname - contain the encoded point cloud as a Blob, and the name of the encoding (LAZ) used for the point cloud. Both of these attributes were originally created by the PointCloudExtractor.
In the PointCloudReplacer’s parameters dialog, Format is set to read the contents of the _pointcloudformatname attribute. We could alternatively set it explicitly to LAZ, if we did not have an attribute providing that information.
Blob Attribute is set to _pointcloudblob, and Remove Attribute is set to Yes, which will remove the Blob attribute once it has been decoded and set as the feature’s geometry.
The output feature now has point cloud geometry, and the Blob attribute has been removed.
Usage Notes
- This transformer only works with point cloud formats. Use the GeometryReplacer for vector formats or the RasterReplacer for raster formats.
Choosing a Point Cloud Transformer
FME has a selection of transformers for working specifically with point cloud data.
For information on point cloud geometry and properties, see Point Clouds (IFMEPointCloud).
Point Cloud Transformers
|
Combines features into a single point cloud. Point cloud and non-point cloud geometries are supported. |
|
|
Adds new components with constant values to a point cloud. |
|
|
Copies selected component values onto either a new or existing component |
|
|
Keeps only specified point cloud components, discarding all others. |
|
|
Removes specified components from a point cloud. |
|
|
Renames an existing component. |
|
|
Alters the data type of point cloud components, and converts component values if required. |
|
|
Reads point cloud features for testing purposes, including any accumulated point cloud operations. No additional operations are performed, and nothing is done with the features. |
|
|
Creates a point cloud of specified size and density, with default component values. |
|
|
Evaluates expressions on each point in a point cloud feature, including algebraic operations and conditional statements, and sets individual point cloud component values. |
|
|
Serializes the geometry of a point cloud feature into a Blob attribute, encoding the contents according to a choice of common binary point cloud formats. |
|
|
Separates point clouds into multiple features, based on evaluating expressions including component values, and creates a separate output port for each expression defined. |
|
|
Merges point clouds by joining points where selected component values match (join key), including x, y, z, and other components. Component values are transferred between point clouds and output is filtered based on matching success and duplication. |
|
|
Sets point cloud component values by overlaying a point cloud on a raster. The component values for each point are interpolated from band values at the point location. |
|
|
Extracts the geometry properties of a point cloud feature and exposes them as attributes, optionally checking for their existence, retrieving component properties, and finding minimum and maximum values. Extents may also be recalculated and updated. |
|
|
Decodes a binary attribute containing encoded point clouds stored as Blobs, replacing the feature’s geometry with the decoded point cloud. |
|
|
Reduces the number of points in a point cloud by selectively keeping points based on the shape of the point cloud. The simplified and removed points are output as two discrete point clouds. |
|
|
Sorts the points within a point cloud by one or more component values. |
|
|
Separates point clouds into multiple features based on component values, color, or first/last return. |
|
|
Calculates statistics on point cloud components and adds the results as attributes. |
|
|
Takes an input point cloud and reconstructs it into an output mesh. |
|
|
Reduces the number of points in (thins) a point cloud by keeping points at a fixed interval, a maximum number of points, or a set quantity of first or last points. Remaining points are discarded. |
|
|
Converts point clouds to point or multipoint geometries, optionally retaining attribute and component values. |
|
|
Applies a point cloud’s scale, offset, or transformation matrix to it, recalculating component values and removing the transformation values. |
Configuration
Input Ports
Input
Features with point clouds stored as attributes.
Output Ports
Output
Features with their geometry replaced by the decoded point clouds.
<Rejected>
Features without a valid, decodable point cloud in the specified Blob Attribute will be routed to the <Rejected> port.
Rejected features will have an fme_rejection_code attribute with one of the following values:
INVALID_FEATURE_CANNOT_READ_BLOB
Rejected Feature Handling: can be set to either terminate the translation or continue running when it encounters a rejected feature. This setting is available both as a default FME option and as a workspace parameter.
Parameters
General
|
Format |
The point cloud format used to decode the Blob. May be set to an attribute value, or specified explicitly. Choices include:
|
|
Blob Attribute |
The attribute from which the blob will be read. |
|
Remove Attribute |
If Yes, the Blob Attribute will be removed from the output feature. |
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click 
beside the applicable parameter. For more information, see Transformer Parameter Menu Options.
Defining Values
There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.
How to Set Parameter Values
Using the Text Editor
The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.
Using the Arithmetic Editor
The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.
Conditional Values
Set values depending on one or more test conditions that either pass or fail.
Parameter Condition Definition Dialog
Content
Expressions and strings can include a number of functions, characters, parameters, and more.
When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.
Content Types
| These functions manipulate and format strings. | |
|
Special Characters |
A set of control characters is available in the Text Editor. |
| Math functions are available in both editors. | |
| Date/Time Functions | Date and time functions are available in the Text Editor. |
| These operators are available in the Arithmetic Editor. | |
| These return primarily feature-specific values. | |
| FME and workspace-specific parameters may be used. | |
| Creating and Modifying User Parameters | Create your own editable parameters. |
Dialog Options - Tables
Transformers with table-style parameters have additional tools for populating and manipulating values.
Table Tools
|
Row Reordering
|
Enabled once you have clicked on a row item. Choices include:
|
|
Cut, Copy, and Paste
|
Enabled once you have clicked on a row item. Choices include:
Cut, copy, and paste may be used within a transformer, or between transformers. |
|
Filter
|
Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output. |
|
Import
|
Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers. |
|
Reset/Refresh
|
Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers. |
Note: Not all tools are available in all transformers.
Reference
|
Processing Behavior |
|
|
Feature Holding |
No |
| Dependencies | None |
| Aliases | |
| History |
FME Community
The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.
Search for all results about the PointCloudReplacer on the FME Community.
Examples may contain information licensed under the Open Government Licence – Vancouver and/or the Open Government Licence – Canada.
Keywords: point "point cloud" cloud PointCloud LiDAR sonar